Transient Rendering
Light Transport and Sensor Modeling at a Finite Speed of Light (30 Billion FPS)
Abstract
The assumption that the speed of light is infinite underlies almost all classical models in computer graphics and computer vision. However, researchers exploring time-of-flight (ToF) sensors, femtosecond imaging, and non-line-of-sight reconstruction operate in a regime where light propagation delays across scene geometry cannot be ignored.
While Kajiya’s classic Rendering Equation provides a rigorous steady-state foundation for light transport, it omits temporal path-length delays. In this work, Adam Smith, James Davis, and I introduced:
- A Generalized Transient Rendering Equation: Incorporating finite propagation velocity and scattering delays into global illumination transport.
- Numerical Approximation Methods: Practical Monte Carlo sampling techniques for simulating ultra-fast wavefront propagation through 3D scenes (equivalent to visualizing light pulse transport at 30 billion frames per second).
- A General Transient Sensor Model: A formal summary measure of transient light patterns linking time-resolved radiance arrival to physical time-of-flight sensor architectures.
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